luhn - w3toppers.com

Check Credit Card Validity using Luhn Algorithm

You can freely import the following code: public class Luhn { public static boolean Check(String ccNumber) { int sum = 0; boolean alternate = false; for (int i = ccNumber.length() – 1; i >= 0; i–) { int n = Integer.parseInt(ccNumber.substring(i, i + 1)); if (alternate) { n *= 2; if (n > 9) { … Read more

Implementing Luhn algorithm using C#

Here are some extension methods that compute a Luhn checkdigit, validate a number with a checkdigit, and add a checkdigit to a number. Tested in .NET 4.5. There are extension methods for strings, ints, int64s and IList. I got some ideas for this from rosettacode.org using System; using System.Collections.Generic; using System.Globalization; using System.Linq; public static … Read more